DE3881939T2 - Use of ofloxacin for the local treatment or prophylaxis of complaints of the roots of the teeth. - Google Patents

Description

The present invention relates to the use of ofloxacin (9- fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido [1,2,3-de] [1,4]benzoxazine-6-carboxylic acid) or its salts for the local treatment or prophylaxis of diseases of the periodontal membrane of the teeth.

Periodontal disease and dental caries are two of the most common dental diseases. In most cases, tooth loss in adults is caused by periodontal disease. Periodontal disease is an inflammatory disease of the periodontal tissue such as the gingiva and includes several types that vary depending on the extent of the disease's progression or the patient's age. In general, these types can be classified primarily into gingivitis and periodontitis. In addition, periodontitis can be classified into senile and juvenile periodontitis.

Recently, it has been suggested that periodontal disease is caused by nonspecific stimulation from dental calculus or dental plaque. However, recent intensive bacteriological and immunochemical studies have shown that some specific bacteria among more than 200 species of bacteria existing in dental plaque are associated with the occurrence of periodontal disease.

These bacteria are in particular those from the groups of Actinomyces, Spirochetes and gram-negative bacteria from the groups Bacteroides, Actinobacillus, Fusobacterium, Capnocytophaga and Eikenella.

In addition, relationships have been reported between some bacteria and some diseases of the periodontal membrane of the teeth. For example, Bacteroides gingivalis is thought to be associated with the occurrence of senile periodontitis. Likewise, Actinobacillus actinomycetemcomytans is thought to be associated with the occurrence of juvenile periodontitis.

Diseases of the periodontal membrane of the teeth have been treated using the following procedures;

1) Removal of calculus to remove sub-gingival plaque and dental calculus from periodontal pockets,

2) Gingivectomy to remove the inflammatory tissue or periodontal pocket, and

3) Root planing to mechanically grind the surface of the tooth root in order to accelerate the adhesion of the gingiva to the tooth roots.

These procedures are effective to a certain extent. However, some patients with specific internal diseases, e.g. circulatory weakness, cannot be subjected to these surgical procedures.

In addition, dentifrices containing germicide or anti-inflammatory agents and pastes for massaging the gums have been used as treatments for periodontal diseases. However, these agents are not yet satisfactory for the Treatment of periodontal diseases. Under these circumstances, there was a great need for a method of treating periodontal diseases that is more effective than these mechanical or surgical procedures.

As described above, certain bacteria are associated with the occurrence of periodontal diseases. Therefore, it can be assumed that the application of an antibacterial agent such as an antibiotic in a suitable form to maintain its effective concentration at wounds of periodontal diseases is effective for the treatment of periodontal diseases. However, this procedure has not been carried out for the following reasons:

i) The bacteria causing periodontal disease have not been identified.

ii) Periodontal disease is usually classified as a chronic inflammatory disease and it takes a long time to treat this disease. Therefore, if an antibacterial agent is used for a long period of time, side effects of the agent may occur or opportunistic infections may occur due to disturbance of the normal bacterial flora in the oral cavity and intestine.

(iii) No suitable method of administration had been proposed. The bacteria causing periodontal disease exist in the periodontal pockets between the teeth and the gums. Since the pockets are anatomically external parts of the body, antibacterial agents are not effectively delivered to them when the agent is administered orally or by injection. Moreover, even when the agent is in the form of a dentifrice, a mouthwash or a gum massager are not transported to the periodontal pockets in any significant amount. Moreover, they are quickly removed by the washing effect of saliva. Therefore, their effective concentration cannot be maintained in wounds of periodontal disease.

After intensive studies to solve these problems, the inventors have found that ofloxacin or its salts have a strong antibacterial effect and that remarkable effects on the periodontal disease of teeth are obtained when ofloxacin and its salts are administered locally to the wounds of the periodontal disease.

The present invention relates to the use of ofloxacin or its salts for the preparation of agents for the local treatment or prophylaxis of diseases of the periodontal membrane of the teeth.

Examples of the salts of ofloxacin include acid addition salts with an inorganic acid such as hydrochloric acid and sulfuric acid or with an organic acid, carboxylic acid salts with alkali or alkaline earth metals such as sodium, potassium and calcium.

Typical examples of pharmaceutical agents for administering ofloxacin or its salts locally to periodontal tissues include gels for the oral cavity, ointments adhering to the membrane of the oral cavity, agents inserted into the periodontal pockets and plasters adhered to the gums.

The agents for local administration can be prepared by mixing an active ingredient, i.e. ofloxacin or its salts, with carriers or vehicles used for agents for the oral cavity, using conventional procedures.

The preferred carriers and vehicles for these agents include hydroxypropylcellulose, methylcellulose, hydroxymethylcellulose, sodium carboxymethylcellulose, hydroxypropylmethylcellulose, liquid paraffin, white petrolate, plastibase, Eudragit L, sodium alginate, propylene glycol alginate, pullulan, tragacanth, xanthan gum, chitosan, polyvinylpyrrolidone, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, ethyl methacrylate, dimethylaminoacetate, cellulose acetate, polyethylene glycol, collagen and atelocollagen.

These substances can be used either individually or in combination of two or more of them, the combination being appropriately selected depending on the form of the agent. These agents may contain a dye or a perfume as additives. Typical examples of these agents are shown below.

When administering these agents, the gels or ointments are applied to the gums, the patches are stuck to the gums and the agents to be introduced into the pockets are introduced there.

The dosage varies depending on the stage of periodontal disease. Usually, an appropriate amount of the agent containing at least 0.01% by weight ofloxacin is applied to the wounds of periodontal disease.

Ofloxacin, which was known as an antibacterial agent (EP-A-0 047 005), has already been used clinically as an excellent synthetic antibacterial agent (see, e.g., Shiota et al., Oral Ther. Pharmacol. (Japan) Vol. 3, No. 1, 1984, pp. 67-77). In particular, it is for oral (Sasaki et al., Oral Ther. Pharmacol. (Japan), Volume 5, No. 2, 1986, pages 78-86; Ohno et al., Chemotherapy (Tokyo, Japan) Volume 32, Suppl.1, 1984, pages 1059-1069; Aderhold and Frenkel, Dtsch. Z. Mund Kiefer Gesichtsschir., Volume 9, No. 5, 1985, pages 394-397), rectal or vaginal

administration (Research Disclosure, 1986, No. 269, pages 519-520) has been used.

Furthermore, ofloxacin-containing compositions for use in the treatment of bacterial eye infections have been described in EP-A-0 142 426. In addition, Gentschew and Stille (Fortschr. Antimikrob, Antineoplast. Chemother. Volume 6, No. 1, 1987, pages 207-215 (Meeting December 6, 1985, Munich)) disclose topical compositions for the treatment of bacterial infections containing ofloxacin. The acute toxicity (LD50 by oral administration) of ofloxacin is 5,450 mg/kg in mice, 200 mg/kg or more in dogs and 500 to 1000 mg/kg in monkeys.

According to the present invention, the use of ofloxacin in a local agent can be used for the treatment or prophylaxis of diseases of the periodontal membrane of the teeth, whereby excellent effects are achieved without disturbing the bacterial flora even at low doses.

According to the present invention, excellent effective concentrations of ofloxacin or its salts in periodontal tissues compared to those obtained by oral administration or administration by injection.

The following examples are intended to describe the present invention in more detail.

EXAMPLES example 1 Gels for the oral cavity:

To 945 g of water was added 50 g of high molecular weight hydroxypropyl cellulose to prepare a gel. 5 g of ofloxacin was added to the gel to prepare a homogeneous mixture for use as an oral gel.

Example 2 Ointments that adhere to the mucous membrane of the oral cavity:

313 g of liquid paraffin was added in small portions to 30 g of ofloxacin to obtain a mixture. 115 g of white petrolatum and 229 g of plastibase were added to the mixture and the resulting mixture was kneaded. In addition, 313 g of sodium carboxymethylcellulose was added and the mixture was thoroughly kneaded to obtain a homogeneous ointment.

Example 3 Agents to be introduced into the periodontal pockets:

250 g Eudragit L30D-55 (30% dispersion), 5 g ofloxacin and 20 g Tween 80 were mixed together. Using a casting technique, a film with a thickness of 300 µm was prepared from this mixture. The film was cut into strips with a width of 1 mm and a length of 10 mm so that it could be inserted into the periodontal pockets.

Example 4 Plasters to be stuck to the gums:

85 g of low molecular weight hydroxypropyl cellulose was dissolved in 1000 ml of water to form a gel. 5 g ofloxacin and 10 g of polyethylene glycol 400 were mixed therein. The mixture was formed into a film with a thickness of 300 µm by a casting method. The film was cut into strips with a width of 10 mm and a length of 100 mm so that it could be used as a plaster to be adhered to the gums.

Test example 1 Effects of ofloxacin-containing gels on experimental periodontitis:

The effects of the gel preparation containing ofloxacin on experimental periodontitis of hamsters infected with Actinomyces viscosus (hereinafter referred to as A. viscosus) were investigated.

18 male, three-week-old golden Syrian hamsters were fed a regular solid diet (CE-2, CLEA Japan Co.) for two weeks. Penicillin G solution (4000 U/ml) was given to them for three days before infection to control their own bacterial flora and facilitate infection. The hamsters were then randomly assigned to one of the following three groups: an infection group to be treated, an infection group not to be treated, and an uninfected group, each group comprising six hamsters. The oral cavity of each animal of the infected group was inoculated with 0.25 ml of culture medium (2.5 x 10⁸ colony forming units/ml; hereinafter referred to as CFU/ml) of A. viscosus ATCC 15987. Bacterial inoculation was carried out daily for five days. From the first day of infection, all animals were fed Diet 2050 instead of CE-2. Diet 2050 was a powdered periodontitis-inducing diet containing 28% sucrose, 28% starch flour, 28% skim milk powder, 6% flour, 4% brewer's yeast, 3% alfalfa powder, 1% liver powder and 2% common salt. After two weeks, 0.1 ml per day of the gels prepared in Example 1 was applied daily to the gums of each hamster.

Eleven weeks after the first bacterial inoculation, the amount of blood hidden in the saliva of each animal was determined using blood occult test papers (Hemasticks III; Miles Sankyo Co.) under anesthesia. The results were classified into five groups from 0 to 4 according to the color standard. The gingival index was estimated and macroscopically classified into 4 groups from 0 to 3 according to the criteria of Rosenberg et al. (J. Periodontol, 37; 208, 1966). Then all hamsters were decapitated. Dental plaque from the first molar of the left maxilla of each hamster was thoroughly scraped off and immediately suspended in an anaerobic Ringer's solution. A 10-fold dilution series was prepared in an anaerobic glove box. The total number of bacteria was counted on a GAM agar culture medium (Nissui Seiyaku Co.), the number of A. viscosus was counted on a selective medium for A. viscosus (J. Clin. Microbiol., 15: 253, 1982) and the number of black-pigmented Bacteroides was counted on kanamycin-vancomycin-menadione blood agar medium (BBL Co.). The plaque index was determined by the method of Regolati and Hotz (Helv. Odonto Acta, 16: 13, 1972) after staining the teeth with a dye (Red-Cote; Buttler Co.). After determining the plaque Index, the jaw bones were removed. The soft tissue and debris were removed from the left jaw bone to obtain a bone sample. Macrographs were taken of each jaw using a stereomicroscope along the tongue side. Measurements of the distances from the cementum-enamel junction to the alveolar ridge were taken for all lingual roots of the molars on the macrograph. The sum of these distances in each hamster was calculated to determine the alveolar bone loss. On the other hand, the right jaw was fixed in formalin, dehydrated, decalcified and embedded in paraffin. It was then sectioned and stained with hematoxylin and eosin. Histological observations of the samples were performed using a microscope.

As shown in Table 1, the degree of periodontitis in the treated group was lower than that in the untreated infected group in terms of blood hidden in saliva indicating hemorrhage from the gingival crevice, gingival index indicating the degree of inflammation of the gingiva, plaque index indicating the amount of plaque, and alveolar bone loss which is particularly typical of periodontitis. The condition of periodontal tissue in the treated group was similar to that of the uninfected group.

The number of bacteria in the plaques in the respective groups is shown in Table 2. In the treated group, the number of A. viscosus used for infection and the black-pigmented Bacteroides, whose pathogenicity had been established in periodontitis, was quite small, although the total number of bacteria was only slightly smaller than in the infected group.

In histological observation, the deposition of a large amount of plaque and the migration of polymorphonuclear leukocytes were observed in the infected group, proving the presence of periodontitis, although these findings are not shown in the tables. On the contrary, they were only slight in the treated group and their extent was similar to that of the non-infected group.

These results indicate that local administration of ofloxacin gel is effective in periodontal diseases, especially in periodontitis.

Test example 2 Comparison of the concentrations of ofloxacin in the oral cavity by oral administration and local administration:

The ofloxacin-containing preparations of Example 3 to be introduced into the periodontal pockets were administered into the pockets of volunteers, and the concentration of ofloxacin in the periodontal fluid in the pockets was measured and compared with the concentration in saliva obtained after oral administration of ofloxacin. In the test, the preparations of Example 3, which had a thickness of 0.3 mm and a width of 1 mm, were cut into strips of 4 mm in length (each strip containing 0.06 mg of ofloxacin). The strip was inserted into a periodontal pocket of each volunteer. The penetration depth of the pocket was 5 mm. After a predetermined time, a filter paper of 1 mm in width was inserted into the pocket to take out the periodontal fluid from the pocket. The amount of ofloxacin in the periodontal fluid was determined from the diameter of an inhibition circle according to an agar plate diffusion method. with E. coli K 12. The amount of periodontal fluid thus removed was determined from a calibration curve obtained by using the amount of a recently prepared fluid sample and the moistened area of the filter paper. The concentration of ofloxacin was thus determined. The time profile of the concentration of ofloxacin in saliva after oral administration was taken from a report by Morihana et al. (Chemotherapy, 32: p.1, 1070, 1984).

The results are shown in Table 3. When 0.06 mg ofloxacin was introduced locally into the periodontal pocket, the concentration of ofloxacin in the pocket remained above 70 µg/ml for more than 5 hours and 16.6 µg/ml even after 24 hours, while the maximum concentration in saliva was 1.8 µg/ml in 3 hours after oral administration of 200 mg of ofloxacin. Namely, when ofloxacin was administered locally into the periodontal pocket in an amount less than 1/3000 of the amount given by oral administration, the concentration of ofloxacin in the pocket could be maintained at higher values than that obtained by oral administration. The concentration of ofloxacin in the periodontal pockets can be maintained for a longer period by varying the composition of the high molecular weight vehicles. Table 1 Results of experiments with periodontitis of hamsters Group Weight gaina (g) Amount of blood hidden in salivab Gingival indexb Plaque indexa Alveolar bone loss valuea (mm) Treated group Infected group Uninfected group Each value is the mean ± standard deviation. a:Examined by Student's t-test ***; p ≤ 0.001, **; ≤ p ≤ 0.01, *; 0.01 ≤ p ≤ 0.05 b:Examined by Mann-Whitney's U-test **; 0.001 ≤ p ≤ 0.01, *; 0.01 ≤ p ≤ 0.05 Table 2 Comparison of the number of bacteria in dental plaques Logarithmic number of bacteria (CFU/ml) Group Total bacteria A. Viscosus Black-pigmented Bacteroides Treated group Infected group Non-infected * No colony was formed at all from Ringer's solution diluted 1000-fold or higher. The other values are logarithmic numbers of bacteria in Ringer's solution and are presented as means ± standard deviation (CFU/ml). Table 3 Influence of administration on the change in concentration of ofloxacin in the oral cavity Route of administration Oral administration* Local administration** Dose Test item (part) Administered agent Time after administration (hrs) Body 8 subjects (average body weight: 60.6 kg) Ofloxacin powder Pocket 8 periodontal pockets of 4 subjects (average depth of pockets: 5mm) Preparation of Example 3 *: Adapted from publication by Morihana et al. (Chemotherapy 32: S1, 1070 to 1083, 1984). The figures are the average concentrations (µg/ml) of ofloxacin in saliva after the oral administration method. * *: The numbers are the average concentration (µg/ml) of ofloxacin in the periodontal fluid in the pockets after introduction of the preparations of Example 3 (1 mm width x 0.3 mm thickness x 4 mm length) into the periodontal pockets.

Claims (2)

1. Use of ofloxacin or its salts for the manufacture of agents for the local treatment or prophylaxis of diseases of the periodontal membrane of the teeth. 2. The use according to claim 1, wherein the amount of ofloxacin or its salts is at least 0.01% by weight in the local preparation.